It’s common for companies to have mission statements. It’s less common to find them painted on conference room walls.

Yet at Lenexa-based Henderson Engineers Inc., employees are challenged to, among other things: “Work hard. Play hard. Mix the rules with imagination. Finish the day knowing that not only was the job done; it was done right.”

Henderson Engineers started with three employees in 1970. Today, 470 people staff seven branches throughout the United States.

President and CEO Duane Henderson began leading the firm in 1989, around the same time that Walmart became a client. By 1991, the company provided engineering work for many of the retail giant’s supercenters. The projects meant steady growth for Henderson Engineers, and in some years, the work force tripled and revenue grew by more than 20 percent.

Twenty-one years later, Henderson’s relationship with Walmart remains solid. In the 1990s, however, Henderson diversified its client base and expanded its services. It now offers a variety of services and works on dozens of types of buildings — everything from criminal justice facilities to religious structures.

Rich Smith, the company’s executive vice president, said Walmart’s stores taught Henderson’s staff how to manage nationwide projects at a time when few other engineering firms could.

Another reason for continuing growth is that Henderson employs well-rounded people.

“We hire and promote people who have the technical ability because at the end of the day they’re engineers, but they need to have people skills, too,” Smith said.

The company’s culture also makes it successful. Smith said that nearly two decades ago, Henderson adopted a work environment with benefits such as flex time and casual dress. Employees have freedom and are encouraged to take on responsibility, and they are rewarded for their work. The firm currently has 31 owners and plans to promote more.

“We get a lot of comments from clients who tell Rich and me how blown away they are by how much these young guys care about what they’re doing,” Henderson said.

The company has a “client-focused culture” and prides itself on being proactive and responsive, said Jim Swords, a principal with architecture firm Populous in Kansas City.

“They’re every bit as good as anybody that we’ve found in the country,” he said.

In order to help the community, Henderson Engineers established a foundation a few years ago.

“We want to reach out to high school kids who might not think about engineering and expose them to the profession,” Smith said. “There’s a projected shortage of technical people, and we want to help.”

Henderson provides numerous scholarships and part-time work for engineering students, and it offers a highly competitive summer intern program.

Henderson also provides pro bono services for Friends of Sacred Structures, supports Habitat for Humanity and participates in the Corporate Challenge and other community activities.

Henderson said that when the economy declined last year, the firm’s leaders sharpened their strategic vision for the future. The firm remains busy with remodeling and retrofit work, but it is providing extensive training so that employees can continue to hone their skills.

Henderson expects this year’s revenue to hold steady or increase slightly from 2008.

“We’ve got talented people with strengths in many areas,” Henderson said. “They’re ready for any opportunities that come along.”